Pneumatic Conveying How to Consider Lifetime Costs for Powder And Bulk Conveying

Author / Editor: Thomas Ramme / Dr. Jörg Kempf

When considering a pneumatic conveying system, the simple purchase price is no longer the most important business criterion. Today, and especially in the chemical industry, the analysis of costs and benefits goes far deeper: More important than a supposedly low purchase price are total cost of ownership and overall equipment effectiveness — especially when dealing with the transfer of powders and bulk materials.

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Modular vacuum conveyors are available in a wide range of designs and sizes.
Modular vacuum conveyors are available in a wide range of designs and sizes.
(Picture: Volkmann)

Vacuum conveyors from Volkmann demonstrate how stainless steel modular design combines with high-performance ejector technology to produce durable, cost-effective systems featuring simple installation and low maintenance. Material to be conveyed is picked up either automatically from a feed hopper or tote bin, or manually by an operator carrying a suction wand. The material is then drawn by vacuum into the bulk material receiver, from where it drops to its destination. This arrangement provides dust-tight feeding from the top without the use of positive pressure.

Often there is a requirement to convey multiple products in the same equipment. To avoid cross-contamination it is desirable that dismantling, cleaning and reassembly should be simple. Manufacturers of paints and coatings using Volkmann technology to convey pigment powders and printer toner (particle sizes 0.2–50 µm) find that they can make major color changes — from black to white — without difficulty.

The Benefits of Modular Design in Stainless Steel Vacuum Conveyors

As well as allowing rapid product changes, modular design in stainless steel meets the stringent hygiene demands of the pharmaceutical and food industries. It also allows individual conveyors to be configured for specific tasks, such as suction modules with special inlets or integrated cyclones. Lightweight and often compact enough to be mounted directly above the equipment to be loaded, the conveyors are also robust, withstanding vacuum down to 90 mbar a.

Combining the bulk material receiver with a stationary or mobile hoist widens the application field even further. As a result, these pneumatic powder transfer systems are increasingly replacing mechanical conveyors including screws, augers, lifts, belts and bucket conveyors.

The optimum configuration for a vacuum conveyor is often found through practical tests. The ease of handling of modular stainless steel systems allows full-scale trials either at the manufacturer’s technical center or on the customer’s site. For testing, a choice of valve types and optional fluidization and discharging aids allow even bridging and sticky powders to be fed.